Automatic fuel shutoff means for combustion apparatus



19-44- A. F. SCHUMANN ETAAL AUTOMATIC FOEL SHUT-OFF MEANS FOR COMBUSTIONAPPARATUS Filed Aug. 15. 1942 PHOTO- ELECTRIC INVENTORS ALFRfD E 5HUMANNBY AND ALEXANDER I TURF/N P0 WEA SOIf/VO/D (ONTROLIED sum/w;

BUTTON 7 Patented Oct. 10, 1944 FFica AUTOMATIC FUEL snu'rorr MEANS roncormcs'rron APPARATUS Alfred 1F. Schumann, Lower Merion, Pa., andAlexmarker .3. Turpin, Stewart Manor, N. Y., assignors to Hanoi:Manufacturing Company, Brookiyn, N. Y., a corporation of New YorkApplication August 15, 1942, Serial No. 454,984

5 Claims. (Cl. 158-28) The invention relates to the operationofcombustion apparatus designed to utilize a variable volume of flowablefuel such as oils, gases, and

powdered solids; and more especially to means for shutting offautomatically the fuel supply to a burner, of the type whose flamelength varies proportionately to the fuel supply, only in the eventthatthe flame discharged into the apparatus becomes extinguished or themixture becomes excessively varied. I

It has for an object to provide, in combustion apparatus having aninitial or ignition zone, instantaneously acting means operative fromconditions prevailing in said zone to shut oi? the fuel supply only whenthe flame becomes extinguished or there is an excessive variation of themixture of the combustible and air.

A further object of the invention is to provide for more effectiveoperation of photoelectric means, heretofore utilized, by causing saidmeans to be so located with respect to direction of propagation of theflame that its axis will intersect said axis of propagationsubstantially at the .far end of a minimum combustion-maintaining flame.i

A still further object of the invention is to so locate thephotoelectric means that its optical axis will clear any emissivesurface of the initial or ignition chamber portion of the combustionapparatus which constitutes a most intense and proximate temperaturezone.

In carrying out the invention, the combustion apparatus is constructedpreferably of an initial or ignition chamber or zone and a combustionchamber coaxial therewith located adjacently to said ignition chamberand in direct communication therewith. A burner directs combustiblematter at the outer end of the ignition chamber into both of saidchambers and the wall of the former chamber is provided with an apertureto the interior of the ignition chamber with which chamber is alignedelectronic means such as a photoelectric cell.

The longitudinal axis of this aperture and the optical axis of thephotoelectric cell are located in a novel manner to secure the objectsof the invention, said optical axis to this end being directed tointersect the axis of flame propagation substantially at the far end ofthe minimum or combustion-maintaining flame. This is at an angle lessthan 45 therewith and substantially 30 for best results. Therelationship between the ignition chamber and the axis of the electronicmeans is such. moreover, that this axis will clear the inner edge of thesurface of the said ignition chamber to avoid reflection from the wallsof the said ignition chamber which constitute a most intense temperaturezone, the wall of the combustion chamber being sumciently remote as notto aflect appreciably the said electronic means.

The nature of the invention, however, will best be understood whendescribed in connectionwith the accompanying drawing, in which:

Fig. 1 is a front elevation of a portion of a furmice with burnerattached and equipped with the novel arrangement for efiecting theshut-off of the fuel supply.

Fig. 2 is a fragmentary horizontal section thereof, shown on a reducedscale, with a diagrammatic representation of the control means.

Referring to the drawing, iii designates the front wall of a furnace towhich is attached by a suitable plate a burner ill of the proportionaltype whereby a flame of variable length may be secured, for example, aburner as set forth in U. S. Letters Patent #2,219,118, #2,219,119, and#2290385, granted to applicants assignee. The

furnace itself is of the type which includes an initial or ignitionchamber i2 terminating in a coaxial, enlarged combustion chamber itwherein the main combustion of the fuel occurs. The minimum. length offlame capable of maintaining combustion is indicated at the flame tip Mand the flame is variable from this length to, for

example, the length indicated at the tip it, these variations beingsecured by correspondingly manipulating the operating handle it ofburner H to vary the volume of fuel.

In accordance with the invention, provision is made for shutting 0d thefuel supplied to the burner H in the event that the flame becomes icallyupon the extinguishment of thee and the means herein indicated beyondthe electronic means may be of the usual well'known type and arrangementfor this purpose. Thus, theleads 20 from the electronic means, such as aphotoelectric cell 2!, are connected to electrical control meansindicated at 22 and fed from a suitable source of power as the mains 28.

From the electrical control mechanism extend I leads 24 to asolenoid-controlled valve 25 which is arranged to shut off the supply offuel to the burner II when the cell 2| is not sufficiently en-' ergized'by the energy radiated from the flame.

A starting connection 26 is also provided to eliminate temporarily theeffect of the cell 2|, all of which is well understood and forms noparticular part of the present invention.

In the present arrangement, cell 2| is associated with an aperture 21through a wall of the ignition chamber, and the longitudinal axis ofprising a single electronic means located at the outer end of theignition chamber and aligned with an opening through the ignitionchamber wall to be responsive to the luminosity of flame therein, theoptical axis of said electronic means being directed to clear the innerend of the ignition chamber and to intersect within the said chamber theaxis of flame propagation substantially at the far end of a minimumcombustionmaintaining flame and to clear the inner edge of the surfaceof the ignition chamber, and means actuated from said electronic meansto control the burner fuel supply.

3. In combustion apparatus including an ignition chamber of reduceddiameter and an adjacent coaxial combustion chamber in communicationtherewith, together with a burner for By this expedient, not only willthe cell 2| be unaffected by any reflections from the inner wall 30 ofsaid ignition chamber which would tend to maintain a supply of fuel tothe burner II, but when the flame has become extinguished by reductionbeyond the length indicated at l4, cell 2| will no longer receiveeffective radiations and will thus shut oil the supply to the burner.Similarly, if the main flame becomes sufliciently weak through atoo-lean or a too-rich mixture of the combustible, the effect of theradiations cent coaxial combustion chamber in communication therewith,together with a burner for flowable fuel discharging in the direction ofthe longitudinal axis of the two chambers to afford a variable lengthflame with variable volume of the fuel: means for shutting off thesupply or fuel to the burner, comprising a single electronic meanslocated at the outer end of the ignition chamber and aligned with anopening through the ignition chamber wall to be responsive to theluminosity of flame therein, the optical axis of said electronic meansbeing directed to clear the inner end of the ignition chamber and tointersect within the said chamber the axis of flame propagationsubstantially at the far end of a minimum combustion-maintaining flame,and means actuated from said electronic means to control the burner fuelsupply.

2. In combustion apparatus including an ignition chamber of reduceddiameter and an adjacent coaxial combustion chamber in communicationtherewith, together with a burner for flowable fuel discharging in thedirection of the longitudinal axis of the 'two chambers to afford avariable length flame with variable volume of the fuel: means forshutting off the supply of fuel to the burner when the flame therefrombecomes extinguished, is reduced to minimum flamemaintaining length, orthe combustible mixture becomes too lean or too rich, said meanscomflowable fuel discharging in the direction of the longitudinal axisof the two chambers to afford a variable length flame with variablevolume of the fuel: means for shutting off the supply of fuel to theburner comprising a single electronic means located at the outer end ofthe ignition chamber and aligned with an opening through the ignitionchamber wall to be responsive to the luminosity of flame therein, theoptical axis of said electronic means being directed to clear the innerend of the ignition chamber and to intersect within the said chamber theaxis of flame propagation at an angle less than therewith, and meansactuated from said electronic means to control the burner fuel supply.

4. In combustion apparatus including an ignition chamber of reduceddiameter and an adjacent coaxial combustion chamber in communicationtherewith, together with a burner for flowable fuel discharging in thedirection of the iongitudinal axis of the two chambers to afford avariable length flame with variable volume of the fuel: means forshutting off the supply of fuel to the burner comprising a singleelectronic means located at the outer end of the ignition chamber andaligned with an opening through the ignition chamber wall to beresponsive to the luminosity of flame therein, the optical axis of saidelectronic means being directed to clear the inner end of the ignitionchamber and to intersect within the said chamber the axis of flamepropagation substantially at an angle of 30 therewith, and meansactuated from said electronic means to control the burner fuel supply.

5. In combustion apparatus including an igni-- tion chamber of reduceddiameter and an adjacent coaxial combustion chamber in communicationtherewith, together with a burner for flowable fuel discharging in thedirection of the longitudinal axis of the two chambers to afford avariable length flame with a variable volume of the fuel: means forshutting off the supply of fuel to the burner comprising a singleelectronic means located at the outer end of the ignition chamber andaligned with an opening through the ignition chamber wall to beresponsive to the luminosity of flame therein, the optical axis of saidelectronic means'being directed to intersect within the ignition chamberthe axis of flame propagation substantially at an angle of 30 therewithand to clear the inner edge of the surface of the ignition chamber, andmeans actuated from said electronic means to control the burner fuelsupply,

ALFRED F. SCHUMANN. ALEXANDER. J. TURPIN.

